Means and method of distance finding



Feb 4, 1936.' TURNERLJR 2,029,347

MEANS AND METHOD OF DISTANCE FINDING Original Filed Sept. 20, 1927STANDARD INDICATOR FDJ'US'IABLE |MPEDANCE INDICATO' INVENTOR. Eowm E.TURNER JR.

ATTOfRNEY.

Patented-Feb. 4, 1936 UNITED STATES.

PATENT OFFICE 2,029,347 MEANS AND METHOD OF DISTANCE FINDING Originalapplication September 20, 1927, Serial No. 220,719. Divided and thisapplication August 2, 1929, Serial No. 383,025

4 Claims. (01. 177452) The present application is a division of mycopending application Serial No. 220,719, filed September 20, 1927,Patent No. 1,991,430, and relates in particular to the system and methoddescribed m me specification in connection with Figure 3 therein. a

The present invention relates to the means and method of controlling therestoration of a relay circuit of the general type herein shown, as wellasthe types of circuits shown in my copending United States patentapplication Serial No. 200,086, filed June 20, 1927, Patent No.1,775,073. In my application just referred to the circuit of the lasttube is restored to normal, preoperating condition by the fact that thegrid return is connected to the positive side of the filament and thatafter the phenomenon has passed the grid assumes the positive potentialof the positive side of the filament. Since this is substantiallyinstantaneous, the circuit is brought back to normal conditionimmediately after operation. In the modification of Figure 3, inapplication Serial No. 200,086, the circuit is restored to normalcondition by operation of the switch 25, which brings the potential ofthe-grid to that of the filament.

The present invention is chiefly concerned with the regulation or therestoration of the circuit to normal conditions automatically but notinstantaneously.

Not only is it possible to adjust the interval between operation andrestoration to any desired .value, but it is also possible, by themethods of the present invention, to vary this interval by propercontrolling devices. If, for instance, it is desired to insure that thecircuit remain inoperative for one second, certain electrical constantsmay be so adjusted, as will be explained later, as

to accomplish this result. A device of this nature is particularlyuseful in recording sound phenomena which are followed by otherphenomena not desired and which, therefore, are eliminated .by makingthe circuit remain inoperative during the necessary interval to excludethe undesired phenomena.

Another useful purpose to which the present invention may be put is themeasurement of a time interval. If the values of the constants of therestoration circuit are known relative to the time interval, thentheinterval between two operations of the circuit occurring directlyat-the beginning and at the restoration of the circuit can be measuredby the constants of the circuit. Theinvention will be described withreference to the drawing, in which: I

Figure 1 shows schematically the circuit of the present system; 7

Figure 2, the application of the circuit to a time regulating system;and

Figure 3, the application of the circuit to the 5 measurement ofdistance.

In Figure 1, l is a sound or other receiver capable of receiving animpulse or the signal for operating the relay l2 of. the output circuitl3. In place of the relay in the output circuit, the im- 10 pulse or thesignal in the transformer winding I I may be made to operate any kind ofindicating circuit which may be desired, as, for instance, a dischargetube such as indicated in my copending application mentioned above.

The impulse from the receiver I may be put through a filter or animplifler 2 and thereafter of the potential upon the grid of the tube Iwithin 25 the range of the voltage used for the filaments.

The plate of the tube 7 is maintained at a potential positive withrespect to the filament by means of the battery 6, which has itspositive side connected to the plate and its negative side con- 30nected through the resistance 9 to the filament of the tube 7. In shuntwith the resistance 9 is a condenser III, the operation of which will beexplained a little later. The plate circuit of the tube I is coupled tothe tube 8 by means of the grid lead l8 connecting from the upper end ofthe Y resistance 9 to the grid of the tube 8. A fila-- ment battery ofnecessary power is indicated between the taps It and I5 and is used tosupply the filaments with heating current while the plate voltage of thesecond tube is supplied by the power source between the terminals 16 andII.

The operation of the circuit is as follows: When an impulse is firstreceived by the receiver I, it

is transmitted through the amplifier or filter 2,

point A and the tendency in ,tube 8 will be for the grid to prevent theflow of electrons from the filament to the plate of that tube.

As shown in my copending application mentioned before, this effect maybe made so rapid that the current will be sharply broken in the platecircuit of the tube 8. This sharp interruption of the plate filamentcurrent of the tube is readily useable for the operation of any desiredsignal or indicator.

As has been stated in the copending application, however, when suchcircuit has been used it has not restored itself automatically to normalconditions; but in the present invention, by the use of the condenser I0and an extremely high resistance 9, it is possible to control therestoration of the circuit by suitably selecting the time constant dueto the presence of resistance and capacity in the circuit. The operationof the circuit of the first vacuum tube causes an increase in its platecurrent and therefore an increase in potential between the points A andB in Figure 1. The condenser l0, which has its charge thereby increased,remains charged until the potential between the points A and B has againdropped after the phenomenon has passed and coil II has been energized.When this has occurred the charge upon the condenser I 0 begins to leakoff and discharge through the resistance 9, thus allowing the point B toreturn to its normal, preoperating condition with respect to the pointA. The rate of discharge of the condenser l0 through the resistance 9controls the period of restoration of the circuit.

By selecting proper values of resistance and capacity in the presentcircuit, it has been possible to delay the normal restoration of thecircuit from a very small fraction of a second to a number of seconds.It is thus possible to allow one operation of the circuit and preventany further operation until it is restored to normal conditions by meansof the condenser and resistance. which may be adjusted for practicallyany desired time interval.

In Figure 2 is shown an application of the circuit for the method ofmeasuring the accuracy of a timing mechanism, such as a watch or clock,against a given standard.

A standard clock or chronometer is indicated at 20 and the watch to betested at 2|; Individual microphones 22 and 23, associated respec-'tively with the standard and'the watch to be tested, are connected incircuit with the transformers 24 and 25 forming the input to the timecontrol circuit of the same type as indicated in Figure 1, with theexception that the condenser l0 and the resistance 9 are variable andadjustable. Also, in addition to the relay coil II and the relay |2, anindicator 26 is shown, as well as switches 21 and 28, the former foroperating the circuit in connection with the coil II- and the relay l2and the latter for operating a neon or discharge tube 29 through thetransformer 30.

The method of operation of the circuit in Figure 2 is as follows: Themicrophone 22 is placed over the standard time piece and the ticks aretransmitted from the time piece through thecircuit either to the neontube or the indicator, either causing a flash of the former or some sortof an indication in the indicator. The ticks of the standard will.therefore be repeated in the same unifornrinterval. The watch to becompared, 2| in Figure 2, will then be placed beneath the microphone 23.Presumably the ticks of the standard and the watch will be out of phaseand follow one another with some definite interval between, whichinterval will gradually change if the watch to be adjusted is not goingproperly. The condenser III and the resistance 9 are therefore adjustedto the point which will just allow the ticks of both the standard andthe watch 2| to come through to the indicator. If, now, after a shorttime, only one tick comes through, it is evident that the time intervalbetween the ticks of the standard and the watch 2| has decreased.

A second adjustment may again be made and, knowing the calibration ofthe condenser and resistance for the equivalent time interval, the lossor gain of the watch over the period is easily determined. If theinterval increases so that both ticks continue to appear, a secondadjustment can still be made to the point where both ticks will justappear. This increased time interval will also give a measure of thechange of the watch with respect to the standard. If, of course, theinterval continues to remain the same, the watch 2| and the standard aregoing alike.

It will be readily understood that if the time interval from the tickingof the standard to that of the watch is increasing, the complementarytime interval from the tick of the watch to that of the standard isdecreasing, and that if it is desired in the measurement and adjustmentto have one tick disappear, the observation can always be made on thedecreasing time interval. In this manner, instead of waiting a longtime, days for instance, to determinethe rate 01 change of a watch witha standard, it may be made much quicker with accuracy.

Another important use of the present invention is in connection with thedetermination of distance by sound and electromagnetic waves. In Figure3 is shown such an arrangement.

Simultaneous signals are sent out by the radio antenna and the submarineoscillator 3| by means of the cams 32 and 33 respectively operating insynchronis m to connect the generator 34 therewith. The signals arereceived on the receiving antenna 35 and the hydrophone 36, the radiosignal on the former and the submarine on the latter. The radio signalis transmitted, through the transformer 31, to the time control circuit,and the submarine signal through the transformer 38 to the same circuit.

An adjustable impedance 39, in place of the condenser and resistance ofFigures 1 and 2, is provided for measuring the time interval between thereceipt of the radio and the submarine signals. This impedance may becalibrated in units of distance as shown in Figure 3.

The measurement may be made either by adjusting the impedance 39 untilthe submarinesignal disappears or by adjusting the impedance until itjust appears. A good method to follow is to make the measurement in bothways and then take a mean value for the distance.

Having now described my invention, I claim:

1. In a system for measuring the distance with the aid of radio andsubmarine compressional waves sent simultaneously and repeatedly from asending station, a receiving system includin a radio and submarinereceiver, a receiving circuit, means for impressing said signals uponthe same receiving circuit said receiving circuit including a pluralityof vacuum tubes having adjustable impedance means coupled betweenvacuum-tube stages for delaying the recovery of the tube connected incircuit after said impedance means following the operation of thecircuit by the signal, an indicator operably connected in the output ofsaid receiving circuit, and a scale'for indicating distances, wherebyafter initial operation of the indicator said im pedance may be adjustedso that the second signal will just not operate said indicator.

2. In a system for measuring distance with the aid otradio and submarinecompressional wave signals sent simultaneously and repeatedly from asending station, means for measuring the interval between the receipt ofthe two signals comprising means for receiving a radio signal, means forreceiving a submarine signal, a single receiving circuit, means forimpressing both said signals upon the receiving circuit and adjustablemeans included in the receiving circuit for making the circuitinoperative for a desiredtime after the receipt of a signal and a scaleassociated with the adjustment of said means whereby. the distance maybe determined.

3. In a method for measuring the distance with a the time intervalbetween the receipt or two signals which comprises impressing thesignals upon the receiving system and allowing them to operate theindicator, varying the time of delay in the time-delay circuit untilonly one signal is indicated and measuring by the amount of delay thetime interval. I

4. In a system for measuring distance with the aid of radio andsubmarine compressional wave signals sent simultaneously and repeatedlyfrom a sending station, means for measuring the interval between thereceipt of the two signals comprising means for receiving a radiosignal, means for receiving a submarine signal, a single receivingcircuit, means for impressing both said signals upon the receivingcircuit, indicating means operated by said receiving circuit upon

